Cellular phones, personal digital assistants, walkie-talkies, garage door openers, computers, routers and other communication devices all incorporate radio technology to establish and maintain communications over the air. Some RF devices, such as cordless telephones, may automatically search for a channel to establish communications and then release the channel when the radio is finished. These radios may operate according to rules, parameters and limitations imposed upon them by government regulation, an owner or operator, a network, radio frequency requirements or limitations of the physical environment. Most of these radios, however, are unable to automatically adapt to significant or challenging changes within the network or environment.
Some of these devices operate within a network, which may be interconnected to other networks such as a public switched telephone network or the Internet. A radio may be part of a network over which it sends and receives information to other radios or devices. A networked radio device typically does not possess the capability of adapting to its operating environment without manual intervention by a user (e.g., by a user manually tuning it to another frequency or channel that has improved reception) or without receiving rudimentary signaling information and instructions from its network.
Networked radios designed to operate within one particular band or sets of particular channels cannot operate outside of the designated band or channels without appropriate authorization from regulatory authorities or spectrum owners. For example, a radio may search a specified band to find an open channel for communications with the network. The radio will sequentially or randomly step or hop through the band until an open channel is found or an indication is given (e.g., through a control signal) that the network is otherwise busy (e.g., no channels are available). Such a radio, however, does not determine a new band or frequency range from which to search for channels if a channel is not found. The radio either works within its prescribed frequency band according to its fixed characteristics (such as transmit power, bandwidth, and modulation scheme) or it does not work at all.
If a typical radio confronts harmful interference, then its communications signals will not be transmitted or received. The radio also might receive a command from a base station to shut down for any number of reasons. For example, under U.S. government regulations, radios operating on certain frequencies in the 5 GHz band must cease transmissions on that channel within a specified time from the detection of radar signals, which have priority over radio transmissions. A typical radio, however, is not able to adjust, or is not agile in the sense that it can determine on its own how to overcome interference problems. Further, if the radio encounters different parameters or a change within its environment that demands different parameters, then the radio were unable to determine the parameters impacted or what behavioral modifications should be made.
For example, public safety radios used by firefighters often have problems working in the basements of buildings on a frequency assigned to the radio. If the radio is able to dynamically sense its environment and adjust its frequency, modulation, power and network parameters, then the radio would be able to maintain connectivity even under challenging conditions. Radios that do not have a dynamic capability to adapt to the environmental and user changes result in a loss of service. Moreover, if regulatory parameters change, then the radios become incapable of being re-programmed to support new rule-sets without costly refurbishing at a facility or location away from the users.
Some radios, known as software-defined radios, can be reconfigured to adapt to a changing environment. These radios, however, are not able to dynamically adjust their operating behavior outside of a predetermined, fixed set of parameters without uploading new software to the radio or modifying its hardware. Furthermore, these radios generally are not able to achieve performance objectives aside from normal communications, such as avoiding interference or conversely, maintaining communications even at the expense of causing interference to radios outside the network or with lower priority.
Other radios use simple spectrum access techniques generally to operate within a single frequency band and strive to achieve basic communications within narrow slices of unused spectrum. These radios/methods, however, are not suitable for operating across a broad cross section of frequency bands.
The headings provided herein are for convenience only and do not necessarily affect the scope or meaning of the claimed invention.